Switching language should update date and time formats

[SergeyBiryukov]

Previously: #11226

1. Install WordPress in English.
2. Switch language to Russian.
3. Date and time formats in General Settings are still F j, Y and g:i a, which doesn't make sense for Russian and doesn't match the locale defaults (d.m.Y and H:i, respectively).

[Clorith]

This would need to account for those who have set their own date and time formats though, so as not to override user settings that may differ from what we expect from a locale.

[swissspidy]

This would need to account for those who have set their own date and time formats though, so as not to override user settings that may differ from what we expect from a locale.

It could work by not saving the date and time formats to the database until they differ from the ones specified by the locale.

[vagios]

In 36259.patch, if the locale's default date/time format is used, after the update the new locale's default values will be used. In any other case the code works as before.

[DrewAPicture]

Related-ish: #28344

[only1andrewh]

Replying to vagios:

In 36259.patch, if the locale's default date/time format is used, after the update the new locale's default values will be used. In any other case the code works as before.

I just tested this patch, and if left on the default time format it changes to the one specific to the chosen country.
Before applying the patch I confirmed that the old local was going into the custom format and active.

[DrewAPicture]

Assigning ownership to mark the good-first-bug as "claimed".

[pento]

Patch needs a refresh, testing, and review.

[ocean90]

#54923 was marked as a duplicate.

[sarumbear]

It is all good to mark https://core.trac.wordpress.org/ticket/54923 as duplicate but this is a six year old bug, which still has no defined milestone. How can we attract attention to it?

I find it strange that a bug that allowed a general setting, which has a dedicated page, to fail for six years. (I assume the code is the same between .com and .org.)

​https://wordpress.com/support/language-settings/

[seepops]

I agree with @sarumbear this seems to be forgotten about. I have custom post types that use the published date and it is confusing and irritating not being able to change the dates in the admin to UK format i.e. dd/mm/yyyy. Please get this looked at.

[jornp]

Screenshot (before, English, default format selected)

[jornp]

Screenshot (after switching to Dutch, the default Dutch formats are selected)

[jornp]

I've updated the patch to work with the current WordPress version. Also, in the original patch, the update_option calls were performed before the translations of the new locale were loaded. I've moved the calls to be performed right after the switch is made.

This patch seems to be working correctly, see the screenshots above. I think this could use some unit tests moving forward.